Industrial equipment is subjected to varying levels of vibration and impact, usually created by operation of the equipment itself, but sometimes transmitted to the equipment from the floor on which it is mounted. Such vibration impairs accuracy of operation, reduces useful life of the equipment, creates noise pollution and causes operator fatigue. Moreover, other plant personnel may experience long term physical and psychological effects resulting from daily exposure to the noise and vibration caused by operation of such equipment.
Such problems can be substantially reduced or eliminated by using anti-vibration mounts to support equipment which either produces or must be protected against vibration. The simplest of such mounts may be pads of cushiony material, placed under the equipment or the supporting structure. In recent years, more advanced mounts have been developed. The more sophisticated isolators, such as those shown and described in my U.S. Pat. No. 3,332,647, granted July 25, 1967, have the additional advantage of permitting precise height adjustment and accurate leveling of the equipments.
For optimum efficiency, all of the isolators supporting a machine should be adjusted with precision to equalize the load supported one each leg of the supporting structure, or to distribute the load in a manner to provide optimum operating characteristics. Heretofore, there has not been any practical way of determining the precise load supported by each isolator on which a machine is mounted so as to provide the information necessary to permit adjustment for optimum load distribution.
In many cases, the weight of the equipment and the location of its center of gravity are not accurately known. The addition of dies, controls and other auxiliary equipment, modifications to the equipment, adjustments in position, and the changing positions of moving parts result in changes in weight and center of gravity, and often introduce changes in inertia forces. These uncertainties and variations make it necessary to guess the static and dynamic load supported on each isolator. Even when the weight and center of gravity location are known, there has been no practical method of determining when the isolators are adjusted to provide optimum distribution of the load supported on the separate isolators, nor to know the magnitude of dynamic forces transmitted to the foundation.
A major purpose of this invention is to provide an adjustable vibration isolating means which has the capability of indicating the force exerted thereon. Another object is to provide such means which shows variations in load during operation of the equipment it serves to support. A further purpose is to enable not only selective or simultaneous read-out as to the load on each isolator, but also cumulative total weight on all the isolators, location of the center of gravity, the transmitted impact forces and the inertia forces generated by the operation of the machine. A further purpose is to provide a means whereby the load supported by the various isolators may be adjusted to provide the most desirable distribution. A further purpose is to provide positive information upon which to base the design of foundations, floors, etc. and to take necessary steps to strengthen such structures if the actual forces as measured by the isolators prove to be greater than originally provided for in the design of the supporting foundation. A still further object is to develop such means which are readily adaptable to existing equipment installations and which are low cost, dependable and versatile. A particularly important purpose is to permit study of force changes which may occur during machine operation, such as cyclical imbalances which affect the stability of the machine, thus indicating the necessity of taking safety precautions or of eliminating unsafe operating conditions.